The present invention relates to an equipment for machining pieces on a pallet by means of a machine tool with a single device for the transfer of pallets between a work station and an adjacent station for loading/unloading the pallets.
A work station for machining pieces on machine tools for milling, drilling, reaming, etc., otherwise known as a work center, is substantially constituted by three main parts:
a lower part, which is a carriage sliding on a fixed base in a direction orthogonal to the axis of the tool-holding chuck of the machine tool which must machine the piece;
an intermediate part, known as a table, which can rotate on the carriage around a central vertical axis and which is made to rotate by an electric motor installed on the carriage and by a suitable mechanical transmission;
an upper part, known as a pallet, which during the machining stage is centered on the table and rigidly integral with it due to the effect of suitable clamping members and which can be disengaged from the table and slid suitably on it along suitable rectilinear guides.
The possibility of the sliding of the pallet on the table is used to transfer the pallet from the table to a support at the same level and provided with similar guides, external to the work center, and to subsequently transfer a new pallet to the table from a similar external support; there is thus accomplished a rapid change of pallets on the table and the operations of releasing and unloading from the pallet of the finished pieces and of loading on the pallet and of holding the pieces to be machined are executed outside the work center, while the latter carries out the machining stage, increasing productivity.
Habitually, the transfer of the pallet from the table to an external support and from the other external support to the table is executed automatically by two distinct transferrers, one incorporated in an external support and the other incorporated in the other external support; each of the two transferrers has its own electric motor, its own transmission of movement and its own electronic control of the movement.
Obviously, due to the displacement of the carriage on the base, the table first moves into line with the empty support, whose transferrer removes the pallet with the finished pieces, and then into line with the other support, whose transferrer delivers to it the pallet with the pieces to be machined.